The Low-Income Housing Tax Credit (LIHTC) is a complex but crucial tool for the production and preservation of affordable rental housing. Despite its broad popularity and almost 3 million financed rental units, it is still not well understood. By enhancing national understanding of LIHTC—how it works, who it serves, and the challenges it faces—this report advances the discussion of how to maximize this vital program’s effects on the production and preservation of affordable rental housing across the country and how to improve its ability to serve low-income households as a key component of our federal safety net.